TY - JOUR T1 - Protective Properties of 2-Acetylcyclopentanone in a Mouse Model of Acetaminophen Hepatotoxicity JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 259 LP - 269 DO - 10.1124/jpet.113.205435 VL - 346 IS - 2 AU - Lihai Zhang AU - Terrence Gavin AU - Brian C. Geohagen AU - Qiang Liu AU - Katherine J. Downey AU - Richard M. LoPachin Y1 - 2013/08/01 UR - http://jpet.aspetjournals.org/content/346/2/259.abstract N2 - Our previous research showed that enolates formed from 1,3-dicarbonyl compounds, such as 2-acetylcyclopentanone (2-ACP), could provide protection in cell culture models from electrophile- or oxidative stress-induced toxicity. In the present study, we evaluated the protective abilities of 2-ACP in a mouse model of acetaminophen (APAP) hepatotoxicity. Results show that oral APAP overdose (500 mg/kg) was nearly 90% lethal within 72 hours and that the resulting hepatotoxicity was associated with substantial changes in plasma liver enzyme activities, histopathological indices, and markers of hepatocyte oxidative stress. 2-ACP administered intraperitoneally 20 minutes before APAP completely prevented lethality over a 7-day observation period. This effect was dose-dependent (0.80–2.40 mmol/kg) and was correlated with normalization of measured parameters. Nearly complete protection was afforded when 2-ACP was administered 20 minutes post-APAP, but not 60 minutes after intoxication. Although intraperitoneal administration of N-acetylcysteine (NAC) was not effective over a broad dose range (2.40–7.20 mmol/kg), temporal studies indicated that intraperitoneal NAC was hepatoprotective when injected 60 minutes after APAP intoxication. Because of a loss of function in stomach acid, oral administration of 2-ACP was associated with modest APAP protection. In contrast, NAC administered orally provided dose-dependent (0.80–2.40 mmol/kg) protection against APAP hepatotoxicity. In chemico studies and quantum mechanical calculations indicated that 2-ACP acted as a surrogate nucleophilic target for the reactive electrophilic APAP metabolite N-acetyl-p-benzoquinone imine. Our findings suggest that 2-ACP or a derivative might be useful in treating acquired toxicities associated with electrophilic drugs and metabolites or environmental toxicants. ER -